Current sensors are used in a wide variety of applications and industries. The sensors can comprise magnetic field sensors to detect a magnetic field related to a current flowing in a conductor and infer the current based on the field measurement. Magnetic field sensors can comprise Hall effect sensors, comprising ordinary Hall plates or vertical Hall effect sensors, or magnetoresistive (MR) sensors, such as giant magnetoresistors (GMRs), tunneling-magneto resistors (TMRs), anisotropic magnetoresistors (AMRs) and colossal magnetoresistors (CMRs), among others. Generally speaking, MRs are devices in which an electrical resistance changes in response to an applied magnetic field. In some MRs (e.g., GMRs, TMRs, CMRs), a reference direction in the sensor is defined by a pinned layer, whereas in other MRs (e.g., AMRs) it is defined by the direction of current flow irrespective of the polarity.
Many conventional magnetic field current sensors include a magnetic core in which the current is guided by permeable magnetic parts. Magnetic field sensor elements arranged proximate the core can detect the current by sensing the magnetic field induced thereby. Drawbacks of these sensors include heat generation due to magnetic losses in the core, increased manufacturing costs, large sizes, increased weights and poor performance. Additionally, in conventional current sensors the conductor is typically covered by a non-conducting coating plus harness which may serve as a ground shield. These coatings (e.g., soft elastomers) have poorly defined geometries which could lead to errors in current measurements. Other drawbacks of these sensors include the limited suppression of background disturbances which could also lead to a reduction in the accuracy of the measured current.